The Arrows of Time: Orthogonal Book Three (38 page)

‘Maybe the Council will finally exercise enough discipline to keep it all quiet,’ Ramiro replied.

‘If they’re capable of that,’ Agata countered, ‘then they’re capable of doing a vastly better job than we are with the entire project.’

Ramiro gave up. He desperately wanted everything to work in the old way, when he could wrap his mind around a self-contained problem and take it apart without having to think about the entire
history and politics of the mountain. But wishing for those days wasn’t going to bring them back. ‘Then we should go ahead with the star-occulters for our hypothetical saboteurs,’
he said. ‘Find a way to build them, and a way to keep them secret, and then hope that the cosmos takes us up on the offer to explain away the disruption with one simple, harmless
conspiracy.’

Agata took hold of one end of the slab of calmstone, Ramiro the other, then they lifted it onto their shoulders and stood facing each other, some four strides apart.

‘Are you ready?’ Tarquinia asked.

‘I’m not sure how steady this will be,’ Agata replied.

‘That doesn’t matter. I just want you to be able to keep your grip when there’s a force applied from below.’

Agata put a second hand on the slab. ‘All right. Go ahead.’ The improvised test rig looked alarmingly amateurish, but the ceiling of the cabin was made of the wrong material, and in
any case they didn’t want to leave it covered with incriminating marks. They’d hunted through the storeroom for something to serve as a trestle, but there’d been nothing
ready-made, so in the end their bodies had seemed like the most expeditious substitute.

Tarquinia pushed a button on the remote control and the occulter rose from the floor. The core of the tiny craft was a dodecahedron about a span wide, with air nozzles fixed in the centres of
eleven of its pentagonal faces. Attached to the top, twelfth face was a linear assembly, a pair of arms three or four spans long, as densely packed with gears and linkages as anything from the age
of clockwork.

Staying low, the occulter steered its way across the cabin until it was hovering in front of Agata’s feet; she could feel the spill of air against her skin. Then it ascended smoothly until
it made contact with the calmstone slab – surrogate for the slopes of the
Peerless
itself. She gripped the slab tightly as four burred tips drilled obliquely into the stone. As
Tarquinia had promised, the net force was purely vertical, so the weight of the slab bore most of it, and with the drills counter-rotating in matched pairs Agata felt no torque trying to twist the
slab sideways.

After a few lapses the drills fell silent and the air jets cut off, leaving the device hanging.

‘Try to shake it loose,’ Tarquinia suggested. Ramiro ignored the invitation, but Agata slid her end gently from side to side, and when this had no effect she grew bolder and began
rocking the slab back and forth. The linkage rattled alarmingly, but the four splayed drill bits remained lodged in place.

‘That’s reassuring, isn’t it?’ she said. ‘The mountain is hardly going to sway like that.’

Ramiro wasn’t so impressed. ‘It doesn’t tell us much about the real hazards. If there’s a hole under the surface, or a powderstone inclusion—’

‘If it comes loose that’s not the end of the world,’ Tarquinia stressed. ‘It can always fly back and reattach itself.’

Agata said, ‘Try the walking mode.’

Tarquinia tapped the remote. The four bits remained fixed in the stone, but the plate on which the drills were mounted began rotating on the end of its arm – or rather, the arm began
rotating around the plate, swinging the entire occulter forward, carrying it from Agata’s end of the slab towards Ramiro’s.

When this repositioning was complete, the four drills at the end of the second arm pushed up against the stone and began biting into it. The new quartet managed to gain purchase with only the
first set bracing them; there was no need to start up the air jets again. Then the first four went into reverse and disengaged from the stone, and the whole process began to repeat itself.

Agata watched anxiously as the machine whirred and clanked its way down the slope from her shoulder to Ramiro’s. If the slab was unrealistically smooth, at least they’d made sure
that it wasn’t gravitationally level.

When the occulter had come within a span of Ramiro’s body, Tarquinia used the remote again. The craft freed itself from the slab and flew away to alight on the cabin floor. Ramiro looked
to Agata, and they carefully put the slab down together.

‘Not bad,’ Tarquinia declared.

Ramiro said, ‘No. But we still need to decide what happens when the surface is uneven.’

Tarquinia had already reached her position on that. ‘It should detour around the problem if it can, or drop away and fly past it if it can’t. That makes it purely a question of
navigation.’

‘And a question of air,’ Ramiro corrected her.

‘Whatever we do,’ Tarquinia replied, ‘there’ll always be a chance of the air running out. Letting the arms tilt so they can conform to the surface won’t guarantee
anything – and it’s one more joint that can jam, two more actuators that can leak, plus six more sensors to make the idea work at all.’

Ramiro turned to Agata. ‘It looks as if it’s your vote.’

‘Can we model the air use for different scenarios?’ she wondered. ‘Take a guess about the roughness of the mountainside, and see what the chances are that we can get these
things from the dock to the antipode with air still in the tank, for each design?’

Ramiro said, ‘I can try, if you want to help me with the model. “Roughness” isn’t the easiest thing to quantify, but you’re the expert on curvature.’

Agata sat beside him and they spent the next three bells working through the problem. In the end, with some plausible assumptions, there was a chance of about five in a gross that the current
version of the occulter would run out of air before it had completed its task. With a new model where the arms could fold together or bend apart – allowing it to keep its grip in bumpier
regions – that fell to three in a gross.

Ramiro said, ‘That’s for a single machine. But even if we build half a dozen spares, we can’t afford too many failures.’

Tarquinia had been doing calculations of her own. ‘You need to add in the chance of the modification itself leading to a failure. I get two in a gross for that.’ Ramiro looked
sceptical, but when he went through her numbers he couldn’t fault them.

‘Five in a gross . . . versus five in a gross.’ Agata couldn’t see how to break the tie. None of these numbers were precise, but without more information she couldn’t
make the uncertainties any clearer.

She looked across the cabin at the occulter. Their encounter with the Hurtler and their bomb-removal project offered plausible excuses for all sorts of items ending up in the void, or lost in
the dust of Esilio – but she was already afraid that their depleted stores might attract suspicion. Ramiro’s proposed changes would require dozens more proximity sensors – spares
that ought to have been packed away neatly in a single large box. Why would they have taken that box out of the storeroom for safekeeping, but then never brought it back?

‘I’m voting with Tarquinia,’ she said. ‘What we’ve got now is physically robust – and we’ll already be hard pressed to build and test the whole swarm
before we arrive. This isn’t the time to start making things more complicated.’

For a moment Ramiro looked poised to respond with a further plea, but then he was silent.

Tarquinia said, ‘It’s good to have that settled. Everyone should get some sleep now, and tomorrow we’ll go into production.’

‘Do you want some fresh pictures for your wall?’ Azelio asked, offering Agata a sheaf of papers.

She took them from him. The first drawing showed the mountain coming into view through the window of the
Surveyor
, with Luisa and Lorenzo standing on the summit waving, very much not to
scale. In the second, they’d thrown out a docking rope to the craft and were reeling it in by hand. ‘These are great,’ she said. ‘Thank you.’

Azelio lingered in the doorway. ‘Come in for a while,’ she suggested. He followed her into the cabin. There was only one chair, so she sat on the edge of the desk.

‘I’m going mad,’ Azelio said bluntly. ‘I don’t know what to think any more. I don’t know what to do.’

‘And I don’t know what to tell you.’ Agata had talked him through the situation a dozen times, but he was never satisfied with her account.

‘Tell me that the mountain won’t be destroyed,’ he pleaded. ‘Tell me that everyone will be safe.’

‘The occulters aren’t looking too bad,’ she said. ‘There are benign ways that the disruption might happen; I can promise you that.’

Azelio glanced down at the pile of notes on her desk. ‘And doesn’t everything that
could
happen, happen? Isn’t that what your diagram calculus says?’

‘No.’ Agata nodded at the pile. ‘For a start, you can only add up diagrams that begin and end in exactly the same way: they all take different paths, but their end points have
to be identical. Getting to the disruption with benign sabotage leaves the mountain intact; getting there with a meteor strike hardly brings you to the same state. And even when the end points are
identical, all the alternatives you draw for a process just help you find the probability that the process takes place. Those alternatives don’t all get to happen, themselves.’

‘Then what makes the choice?’ Azelio pressed her. ‘When a luxagen could end up in either of two places, how does just one get picked?’

‘No one knows,’ Agata confessed. ‘In the years after wave mechanics was developed, there was a big debate about whether it was truly random, or whether there was some hidden
structure beneath the randomness where all the results were certain. For a while, one group of physicists claimed to have proved that there couldn’t be a deeper level. Their proof looked
quite persuasive – until Leonia showed that it was tacitly assuming that information could never flow back in time.’

‘Ah, the strange things people once believed,’ Azelio observed dryly.

Agata said, ‘No one believed it, even then, but they found it easier than we do to forget that it wasn’t true.’

Azelio lifted a diagram from the stack. ‘So what can this tell us about the disruption?’

‘Nothing.’ Agata wasn’t sure how he’d ended up clutching at the diagram calculus as an answer to their plight, but if she’d been careless in describing her work to
him in the past then what she owed him now was as much clarity as she could muster. ‘Just because we don’t know the cause of the disruption, that doesn’t mean that every cause we
can imagine will coexist. If you want history to unfold a certain way, forget about wave mechanics. What matters now are the usual things: who we are, what we do, and a certain amount of dumb
luck.’

Azelio put the diagram down. ‘So if there’s a meteor coming, how do I stop it? Or avoid it?’

‘You can’t,’ Agata replied. This was the sticking point they always reached. ‘Not if the disruption is the proof that it hits us.’

‘Then what difference does it make “who we are” and “what we do”?’ Azelio asked bitterly. ‘If I go through the motions of enacting something more benign
. . . how will that help? If there’s a murderer trying to kill your family, you don’t protect them by moving your own tympanum to match the threats being shouted through the door. Or do
you really believe in safety through reverse ventriloquism?’

Agata wrapped her arms around her head in frustration. ‘We don’t
know
that there’s a murderer at the door! We don’t
know
that there’s a meteor on
its way!’

‘So we search the sky,’ Azelio pleaded. ‘We make better detectors. We try to peek through a crack in the door.’

‘If we were going to find anything,’ she said, ‘we’d know that already. If we were going to spot a meteor and avoid it, then that’s what the messages would be
telling us.’

Azelio said, ‘I can’t accept that.’

Agata dropped her arms. ‘I know.’ There was nothing she could say that would change his mind, and nothing she could do that would bring him any comfort.

‘We should fly over the antipode,’ Tarquinia joked. ‘Do a little reconnaissance.’

‘Fly low enough and you could occult all the channels at once,’ Ramiro suggested. ‘Maybe there’s a disruption earlier than everyone claimed, and all the later messages
are just fakes.’

Agata said, ‘I’d rather not test the defences.’

Through the window, the mountain cast a sharp silhouette against the star trails. It had been visible through external cameras for days, but they’d had to wait until they cut the main
engines to rotate the
Surveyor
around for a naked-eye view.

‘Ah, look at that!’ Tarquinia gestured at her console, which was displaying a feed from the telescope. ‘I think we’ve found a Councillor at home.’ The grey hull
that the instrument had picked up was lurking in the void, far from the
Peerless
. It wasn’t quite identical to the
Surveyor
, but the overall design was eerily similar. Agata
wasn’t shocked that anyone with the means to do so had withdrawn to a safe distance from the mountain, but it was dismaying to see that Ramiro’s guess had been right: even Verano had
lost his powers of originality.

Azelio joined them, taking his seat and murmuring greetings. As subdued as he was, he seemed ready to make an effort to get through the formalities to come. Agata wished she could have assuaged
his fears, but from a coldly pragmatic position she couldn’t help thinking that his forlorn demeanour might serve as useful camouflage. No one observing the whole crew together could imagine
them possessing even the shyest hope of influencing the fate of the
Peerless
.

Tarquinia brought the
Surveyor
spiralling in towards the docking point, and as the mountain finally hid the stars Agata felt a rush of pure joy. She wanted to burrow deep into these
old, familiar rocks again, to drift along the core of an ancient stairwell, to gaze across a field of wheat that stretched beyond the ceiling’s horizon. She glanced over at Azelio and he met
her gaze with a look of shared relief, the sheer force of belonging overpowering his anxiety. How could they not feel safe here?